Magnetic alloy



Patented Apr. 27, 1926.

UNITED STATES PATENT FFIE.

WILLOUGH BY STA'IHAM'. SMITH, OF BENCHAMS, NEWTON IPOPPLEECRED, ANDHENRY JOSEPH GARNETT, 0]? SEVEN OAKS, ENGLAND.

MAGNETIC ALLOY.

No Drawing. Original application fllcdj'anuary 10,1924, Serial No.685,432. Divided and this application filed May 2, 1925. Serial No.27,593.

To all whom, it may concern:

Be it known that we, WILLOUGHBY STATHAM SMITH, a subject of the King ofGreat Britain, residing at Benchams, Newton Poppleford, Devonshire,England,.and

HENRY JOSEPH GARNE'I'T, a subject of the King of Great Britain, residingat Lymne,

Solefields, Seven Oaks, Kent, England, have invented anew and usefulImprovement in Magnetic Alloys, of which the following is aspecification.

This application is a division of our application Ser. No. 685,432,filed J anuary 10, 1924.

This" invention relates to the production of alloys possessing a highmagnetic permeability especially at low magnetizing forces.

It is well known that it is desirable to add Q inductance to telegraphicand telephonic cables and this \has before been done by wrapping aroundthe core of the cable an iron tape or wire.

Many researchworkers' have been inves- '25 tigating the properties .ofvarious alloys,

especially those. of nickel and iron, with a view to discovering analloy'that should be suitable for this purpose. In our researches wehave found that an alloy may be made of nickel, copper and iron, whichhas a low hysteresis loss with a very high permeability at lowmagnetizing forces such as those present intelegraphic and telephoniccables. According to our invention" we make an alloy of nickel, iron andcopper, the nickel predominating, that is being at least 71% of thewhole, while the iron is between 19 and 21% and copper between 5 and 6%.

In order also to increase the electrical resistance of the alloy wepreferably add to it a fourth element which may be tungsten, chromium,silicon, vanadium, titanium, molybdenumor aluminium 3 the amount of thisfourth element is small compared to the amount of copper and ispreferably less 7 than 1%, since the addition of more than 1% of thisfourth element, though inereas--' ing the resistance, will impair thepermeability of the alloy considerably.

We also preferably include a small amount of manganese to render thealloy more easy to forge.

The following are examples of alloys made in accordance with ourinvention An alloy consisting of Per cent. Nickel 74.0 Iron 20.0 Copper5.3 Manganese, 0.7

has an initial magnetic permeability of 7000.

An alloy consisting of Per cent. 'Nickel 73.0 Copper 5.4 Iron .-z- 20.7Tungsten 0.6 Manganese 0.3

has an electrical resistance of'25 m crohms per cubic centimetre and aninitial magnetic permeability of 6600.

An alloy consisting of Per cent.

gickel 73.0 opper 5.4: Iron 20.7 Silicon 0.6 Manganese 0.3

has an electrical resistance of 28 microhms per cubic centimetre and aninitial magnetic permeability of 5000.

has an electrical resistance of 31 microhms per cubic centimetre and aninitial magnetic permeability of 4700.

An alloy consisting of Percent. Nickel. 72.5 Copper 5.5 Iron 21.0Aluminium 0.7 Manganese 0.3

has an electrical resistance of 25.5 microhms per cubic centimetre andan initial magnetic permeability of 5500.

As has been said above, by increasing the amount of the fourth elementthe resistance may be further increased but the permeability may beconsiderably aiiected.

An alloy consisting of:-

Pcr cent. Nickel 72.6 Copper 5.3 Iron 20.6 Silicon 1.2 Manganese 0.3

has an electrical resistance of 32 microlnns Examples.

Alloy No. 1, when heated to 600 C. and cooled in air, has an initialpermeability of 800, when heated to 700 C. a permeability of 2600, andwhen heated to 890 C. a permeability of 7000.

Moreover, when collectively annealed for high initial permeability, thealloys have low hysteresis losses varying from to 150 ergs'per cubiccentimetre with a maximum field of .25 c. g. 5. units.

What we claim is I 1. An alloy comprising nickel to the amount of atleast 71%, iron to the amount of between 19%-and 21% and copper to theamount of between 5% and 6%.

2. An alloy consisting of nickel 74%, iron 20%, copper 5.3% andmanganese .7%.

3. An alloy consisting of nickel to the amount of at least 71%, iron tothe amount of between 19% and 21%, copper to the amount of between 5%and 6% and a. small quantity of manganese.

4. An alloy comprising nickel to the amount of at least 71%, iron to theamount of between 19% and 21%, copper to the amount of between 5% and6%, a small quantity of manganese and tungsten.

5. An alloy comprising nickel to the amount of at least 71%, iron to theamount of between 19% and 21%, copper to the amount of between 5% and 6%and tungsten.

6. An alloy comprising nickel to the amount of at least 71%, iron to theamount of between 19% and 21%, copper to the amount of between 5% and 6%and a fourth element adapted to increase the electrical resistance ofthe alloy.

7. An alloycomprising nickel to the 1 amount of at least 71%, iron totheamount 5 of between 19% and 21%, copper to the amount of between 5%and 6%, another element adapted to increase the electrical resistance ofthe alloy and a small quantity of manganese.

In testimony that we claim the foregoing as our invention we have signedour names this 21st day of April, 1925.

WILLOUGHBY STATHAM SMITH. HENRY JOSEPH GARNETT.

